driving me crazy. actually had it at toyota dealership for a new trans last summer and they could not find the issue? when hitting bumps it makes a loose heavy rattle like something is loose. suspension was looked over and struts and was told all looks good. ball joints look ok. its hard to tell when making the noise where it is coming from ? it has been getting louder as of late thinking maybe like a motor mount maybe? anyone have a clue as to what it might be?